A commercial telecommunications network operated by a service provider typically supports voice and/or data communications between various customer locations served by the network. An overall communications system may be subdivided into an access network and a core network, which may or may not be owned and operated by different service providers. Generally, customer devices communicatively couple to the access network which, in turn, connects to the core network. The access network includes what many people refer to as “the last mile,” that is, the connectivity from a customer location, such as an office building, to a point where a service provider has significant facilities, such as a metro hub or a “service edge” at the periphery of the core network. In contrast to the access network, the core network usually provides transport of large aggregate flows over long distances and handles the selective routing of each customer's voice and data traffic to other locations served by the network.
An access network generally comprises communications links, switches, aggregators, multiplexors, demultiplexors, routers, hubs, and the like which provide connectivity between the customer's equipment and the core network's service edge. In a complicated network architecture involving a large number and variety of equipment and a number of possible points of failure, it is important to a service provider to be able to quickly and efficiently isolate problems or failures in the network. Problems may include a failed piece of equipment, a cut cable, or the like. Many systems are currently employed by existing service providers to provide alarms or warnings when a piece of equipment fails or is suffering degraded performance and may be about to fail. The existing systems are generally focused on monitoring the operational status of the network equipment, such as the switches, aggregators, multiplexors, demultiplexors, routers, amplifiers, and the like located in the service provider's facilities or collocated at facilities operated by a telephone company. These systems, however, fail to indicate when problems exist in equipment installed in the customer's site. Consequently, when a customer experiences loss of access connection to a service provider, a customer may often assume that the problem resides in the service provider's facilities when the problem may actually be in the customer's network or at the point where the customer connects to the service provider's facilities at the customer location.
A common network protocol used by customers is Ethernet. Ethernet provides a cost effective and easy to implement solution for the customers' networking needs, such as LAN and WAN capabilities. A company may have an Ethernet LAN with a port of a network switch or bridge being communicatively coupled to an access switch via a Very high bit-rate Digital Subscriber Line (VDSL), a 10/100 Ethernet, a Gigabit-Ethernet (GbE), or the like. There is no mechanism, however, to indicate when the access switch has lost connectivity to the router. Thus, if the physical cable on the customer's router becomes disconnected or damaged for some reason, errors would be propagated throughout the system as each device would begin to see problems in the communications with the customer's equipment. Many times, the errors generated by the network would provide no probative value in isolating the cause of the problem to a disconnected cable.
To isolate and correct these problems, it is common for service providers to dispatch equipment and service personnel to one or more sites to perform on-site diagnostic tests. Such an error-recovery procedure is time consuming and expensive, particularly when the problem may actually be that the cable connected to the customer's router or switch has simply became disconnected. Thus, there is a need to indicate when connectivity between the access switch and the customers' equipment fails or to detect and isolate other types of fault conditions.